Combined step and guide bearing for turbines.



R. H. RICE.

COMBINED STEP AND GUIDE BEARING FOR TURBINES.

2 1 9 1 r0 1 M 0 d m m M P 0 9 1 6 R A M D E L I I N 0 I T A o I L P P A2 SHEETS-SHEET 1.

Invfintor; Richard .Rice, ByWQ Uy Witnesses:

COLUMBIA PLANOURAPH cu., WASHINGTON, D c.

R. H. RICE.

COMBINED STEP AND GUIDE BEARING FOR TURBINES.

APPLICATION FILED MAR. e, 1907.

1,041,512. Patented Oct. 15,1912.

2 SHEETS-SHEET 2.

Witnesses:

Inventor, Rlchard H Rice,

7 1th. y.

COLUMBIA PLANOGRAPH co., WASHINGTON. 01c.

UNITED TAE ATENT FTQE.

RICHARD H. RICE, O1 LYNN, MASSACHUSETTS, ASSIGNOR T0 GENERAL ELECTRICCOMPANY, A CORPORATION OF NEV YORK.

COMBINED STEP AND GUIDE BEARING FOR TURBINES.

Specification of Letters .Patent.

Patented (bet. 15, 1912.

Application filed March 6, 1907. Serial No. 360,855.

To all whom, z't may concern:

Be it known that I, RICHARD H. Bron, a citizen of the United States,residing at Lynn, county of Essex, State of Massachusetts, have inventedcertain new and useful Improvements in Combined Step and Guide Bearingsfor Turbines, of which the following is a specification.

My invention has for its object to provide a combined stepandguide-bearing of improved construction and is intended more especiallyfor elastic fluid turbines.

In carrying out my invention the lower block of the step-bearing for theupright shaft is supported by the bottom wall of the turbine base, whichbase contains a chamber that receives the exhaust steam from the wheelbuckets. In order to avoid the possibility of a change in position ofthe bottom wall of the base due to any cause such, for example, as thatdue to change in pressure or temperature affecting the alinement of saidbearing with respect to an upper hearing, the opposed surfaces of thestep-bearing are made spherical, and lubricant under pressure iscontinuously supplied to the center thereof in suflicient amount andunder such pressure as will maintain a film between the blocks at alltimes. The lower end of the upright shaft is also provided with aguide-bearing carried by the base wall and having a spherical seat forthe reason above set forth, and this seat and the spherical surfaces ofthe step-bearing blocks are struck from the same center; from this itfollows that both the step and. guidebearings are self-alining. Thelubricant after passing between the step-bearing blocks flows throughthe guide-bearing after which it is returned to the supply. Preferably,but not necessarily, the upper guide-bearing above the turbine is alsoprovided with a spherical seat. By reason of the construction describedthe operation of the turbine .will not be affected, even though theshaft be slightly sprung.

Tn order to prevent the condenser connected to the chamber in the baseof the machine from sucking lubricant from the guide-bearing, a packingis provided comprising an impeller rotating in a body of liquid such aswater in the chamber inclos ing it. and by the pressure created forminga liquid seal. The impeller is not in contact with the walls of thechamber, hence changes in position of the parts will not affect it andno adjustment is required, a very desirable construction where the partsare relatively inaccessible. As a further precaution to prevent theescape of lubricant when the condenser is in operation and the impelleris not rotating a stationary packing is provided such, for example, as acarbon ring that engages a rotating part of the turbine and is carriedby a suitable casing.

In the accompanying drawings, which illustrate one of the embodiment-sof my invention, Figure l is a view in elevation of a vertical-shaftturbine of the Curtis type; Fig. 2 is an enlarged axial section of thelower guideand step bearing; and Fig. 8 is a partial plan view of therotary element for creating a fluid pressure to prevent the admission ofair to the vacuum chamber of the turbine when the machine is operatingcondensing and the escape of water.

1 indicates the base of the machine containing the chamber that receivesthe exhaust from the last bucket wheel, which chamber is connected to acondenser by the conduit 2. lri'ounted on top of the base is a casing 3containing the usual nozzles, wheel and intermediate buckets, andpartitions for dividing the casing into wheel compartments or stages.Mounted on top of the casing is a stool at that supports the stationarymember of the generator 5. Mounted on top of the generator is a cover 6that supports a dome 7, the latter inclosing the upper end of the shaftand the speed governor. The revolving element of the turbine and also ofthe generator is carried by a shaft 8 shown in dotted lines. The weightof the shaft and attached parts is carried by a stepbearing as willappear hereinafter. The shaft is guided by self-alining bearings at theends.

Referring to Fig. 2, 9 represents the base of the machine or othersupport which is provided with a central opening to receive the casing10 of the stepand the lower guide-bearings. This casing is provided witha flange 11 that is bolted to the under side of the base. The lower endof the easing is provided with a head 12, and between the casing and thehead is an annular shoulder to center the head. The head is bored outcentrally to receive the cylindrical guide 13 that is formed on orattached to the lower block 14 of the step-bearing.

lvlounted in the head is a nut 15 which is prevented from turning by theupright pins 16 or equivalent means. iassing through this nut is ascrew-threaded adpising L bolt 1'? having an exposed head or other meanswhereby it can be adjusted in a vertical direction. The adjusting boltextends upwardly through the cylindrical portion of the lower block andengages a seat 18 mounted thereon. The adjusting bolt bored centrally toreceive the conduit 19 for continuously conveying lubricant undersuitable pressure to the parts. The upper end of the conduit is threadedto the seat 18 of the lower block. Tie upper surface of the lowerblOCl-I forrns a portion of a sphere and con-rains a chamber thatreceives lubricant under high pressure. The upper hearing block 20 has alower spherical surface struck from the same radius as the bearingsurface of the lower block. In the under surface of the block is achamber that registers with that in. the lower block, and the chamber 21thus formed is filled with lubricant under high pressure, whichlubricant flows, outwardly in a thin film between the opposing surfacesof the blocks. The lower end of the shaft 8 is seated in a socket formedin the upper block. The end of the raft is chanfiered slightly so as toinsure a good tit between the shaft and the block. Since there isliability of the end of the shaft being slightly curved due to theaction of the cutting-elf tool when the shaft is made, the block isrelieved at 22 so that the shaft rests only on the block near itsperiphery. The shaft and upper block are united by the key 23, thelatter being secured to the block and extending across the end of theshaft from side to side. .lin addition to this, pins are provided thatserve to prevent relative angular movement of the shaft and block andalso serve as a means for guiding the shaft into place in the socket.The casing 10 is provided. with an internal shoulder 25 that supportsthe head 26 which forms a part of the seatfor the guide-bear ing.Between the head and its support is a shoulder which serves to centerthe latter. The head is secured in place by a number of bolts that alsosecure the upper head in place. The bearing seat on the lower head .26is made spherical and said surface is struck from the same center as thesurfaces of the stepbearing. Mounted on top of the casing is head 28,which head is center d by means of shoulder formed on the under surfaceand engaging with an annular shoulder on the casing. This head forms apart of the guide-bearing seat and is provided with a spherical surface29 that struck from the same center as the seat on the lower head andalso the opposed surfaces of the step-bearing blocks. Located betweenthe heads 26 and 28 and engaging earners ing. This pin fits losely intoa longitudinal slot formed in the member 30, which slot is open at theupper end so that. the sleeve can be inserted in place from below. Thelining 31 is provided with vertically extending grooves which. receivelubricant at the lower end and discharge into the channel at the upperend. As many of these channels may be provided as are necessary; I havefound in actual practice that eight are su'l'licient.

It sometimes happens that lubricant will be forced past the channel 82into the space directly above the guide-bearing, and in order to preventit from being carried up beyond this space into the chamber receivingthe exhaust from the liquid seal passages 36 are provided, as shown indotted lines in the head 28. Under normal conditions the sleeve 30 isstationary and hence lubrication is unnecessary; but in order that itmay be free to adjust itself to compensate for any lack of alineinentdue to distortion or otherwise, annular oil groves 37 are provised atthe top and bottom. The lubricant collected in the annular chamber 34-is fed by the pi 1e 38 back to the suction side of the pump.

The pressure of the lubricant admitted by the pipe 19 to the chamber 21is sui'licient to slightly separate the blocks, and the pressure of thislubricant is gradually decreased until it reaches the chamber 39surrounding the step-bearing blocks where its pressure is substantiallythat of the atmosphere. This chamber is always filled with lubricantwhen the machine is in operation and the escape therefrom is through thevertically disposed grooves in the babbitt lining, the annular channel32, passages 33, chamber S-"l: and exhaust pipe 38.

Since most of these turbines are intended to operate condensing, it isnecessary to provide means for preventing the lubricant from the stepandguide-bearings from flowing into the exhaust-receiving chamber in thebase, the pressure of which is commonly about one pound absolute, andtherefore tends at all times to draw lubricant from the bearings. Thismeans includes an element l0 mounted on the shaft and held in placeagainst a shoulder thereon by the radial screw ll. The said element isprovided with a downwardly turned flange 42 having sets of vanes 43 and4-4: mounted thereon. Under certain conditions it is possible to useonly one set of vanes, but I prefer to use a double set as shown. Thesevanes rotate in a pressure chamber 45 that is formed between an inwardlyextending shoulder or projection 4-6 on the head 28 and the innerinclined wall of the cap e7. Between the internal inclined projection 46and the annular extension 48 on the head 28 rising above the bearingseat is formed an exhaust chamber 49 through which the water from theliquid seal flows by gravity to the pipe 50. In order to save space,decrease the number of parts and the machine work, the exhaust chamber,extension 48 and the wall or projection as are located in the head 28forming the upper portion of the seat for the guide-bearing, but theparts and the chamber may be formed in a separate piece if desired. Thepressure chamber is constantly supplied with water from a suitablesource, such as the city service main, by a pipe 51, and a continuousflow is maintained subject to the control of a hand valve. As theelement 40 is rotated the sets of vanes L3 and id act by centrifugalforce to create a pressure in the chamber of sufficient amount toovercome the tendency of the vacuum to suck oil from the bearings. Whenthe parts are in operation, the cross-section of the column of fluid inthe chamber is U-shaped and ordinarily the legs of the U aresubstantially of the same length, but as the absolute pressure due tothe concenser changes, one leg will become longer or shorter than theother, depending upon said pressure.

in order to keep the water discharging "rom the pressure chamber 45separate from the lubricant supplied to the bearings, a'

downwardly extending lip or flange 52 is provided that overhangs theannular pro ection or extension 49 on the upper head 28 of the guidebearing. In order to avoid any tendency for the water to back up in the,

chamber 49, an air vent 53 is provided, the inner end of which extendsbeyond the line of discharge of the lip 52 on the rotatingv member 40.The object of this latter feature is to prevent the water dischargedfrom said lip from directly entering the air vent and thus escaping.

Since it sometimes happens that it is desirable to shut down a machinewithout shutting down the condenser, it follows that unless suitablemeans are provided to prevent it, air will leak into the condenser fromthe chamber 49 or through the joints of the various parts, because whenthe turbine is stationary the liquid seal is ineffective. The

side, and surrounding and engaging this flange is a packing 55 ofsuitable construction. In the present case I have shown a packing madeof carbon which is normally pressed by springs into engagement with saidflange. The packing is mounted in a recess 56 formed in the cap althoughit may be in a separate piece if desired. The cap is secured to theupper head 28 of the guidebearing by bolts 57. In order to permit of thecarbon packing ring being inserted in its recess the cap is made inparts, the plane of division extending axially. Bolts or other means areemployed to unite the parts of the cap. Mounted on the shaft above thecarbon packing is a bucket wheel 58 located in the chamber in the baseof the turbine which is held in place by a nut 59, the latter beingscrew-threaded to the shaft.

In event of the stepand guide-bearings being carried by a support insuch manner that the vacuum exerts no effect on the lubricating system,I may omit the liquid seal and also the carbon packing ring.

In accordance with the provisions of the patent statutes, 1 havedescribed the principle of ope 'at-ion of my invention, together withthe apparatus which I now consider to represent the best embodimentthereof; but I desire to have it understood that the apparatus shown isonly illustrative, and that the invention can be carried out by othermeans.

W hat I claim as new and desire to secure by Letters Patent of theUnited States, is,-

cured to the casing and a lower member detachably secured to the casing,which when detached and lowered permits the guide bearing to be loweredwithout disturbing the casing and the shaft, and a step-bearing, thelower block of which is carried and guided by the casing, the opposedsurfaces of the bearing being spherical and havin the same center as thespherical surface or the guide-bearing.

2. In a turbine, the combination of a vertical shaft, a casing having acentral bore, a guide-bearing for the shaft having a spherical outersurface, a seat therefor comprising a member which forms the upper endof the casing and a second member that is smaller in diameter than saidbore and is attached to the interior of the bore adjacent the upper endthereof, the end of the shaft projecting through the guide bearing andsaid second member into the bore, a step-bearing for the projecting endof the shaft arranged within the bore of the casing below said secondmember, the opposed surfaces of the stepbearing being spherical andhaving the same center as the spherical surface of the guidebearing, anda detachable head secured to the casing at the lower end of the herewhich supports the step-bearin 3. in combination, a vertical shaft, aguide-hearing comprising a lining and a sleeve with a spherical surface,a seat therefor, a step-bearing comprising a rotatable and a stationaryblock having opposed spherical surfaces, a means for adjusting one ofthe blocks vertically, a guide for the means, and a casing for thebearings.

i. in combination, a vertical shaft, a guide-bearing therefor having aspherical surface, a step-bearing for the end of the shaft arrangedbelow the guide-bearin g and including blocks having opposed sphericalsurfaces, the said surfaces being struck from the same center, aninternally shouldered casing for the bearings, an upper head mounted onthe top of the casing, a lower hear mounted inside the casing andattached to the under side of the shoulder, the said heads engaging tieguide-bearing and forming a seat therefor, means by which the lowerstepbearing block is mounted in the casing and guided for iongitudinalmovement therein, and a device for adjusting said block.

in combination, a vertical shaft, 'a sleeve surrounding the shaft andhaving a spherical surface, a lining for the sleeve, a spherical seatfor the sleeve, a step-bearing comprising a stationary and a rotatingblock, the opposed surfaces of which are spherical, the said s hericalsurfaces of the seat and the blocks beil'g struck from the same center,a guide and a support for the lower step-bearing block, a means for adjusting the position of the lower block in the support, and a means forsupplying lubricant under pressure to the central portions saidspherical surfaces.

6. in combination, a vertical. shaft, a guide-bearing having a sphericalseat, a stepdaearing including blocks having opposed spherical s faces,one rotating on the other and secured to the shaft, the spherical.surfaces of the seat and blocks being struck from the same center, acasing common to the bearings, a detachable head for the casing thatsupports and guides the vertical movements of the lower step-bearingblock, and a pair of heads also attached to the cas ing that engage theguide-bearing above and below its central portion and form a seattherefor, the lower head being removable from the underside through theopening normally covered by said detachable head.

7. In a turbine, the combination of a base which is subject to changesdue to pressure and temperature variations, in combination with aguide-bearing for the lower end of the shaft having a spherical seat, astepbearing for supporting the weight of the shaft comprising rotatingand a stationary block, the opposed surfaces of which are spherical andstruck from the same center as the seat of the guide-bearing, a casingcontaining said seat and supporting the lower step-bearing block, meansfor attaching the casing to the turbine base, and a screw for adjustingthe position of the stepbear-in 8. in a turbine, the combination of aver tical shaft, a guide-bearing therefor through which the shaft isvertically adjustable, a spherical seat for the bearing, a step-bearingfor the shaft comprising relatively rotating blocks, the opposedsurfaces of which are spherical and struck from the same center as thesaid seat, a guide for the lower block, an adjusting means for raisingand lowering the shaft and the step bearing in respect to the guidebearing, and a wall for supporting the adjusting means that is subjecttodistort-ion due to temperature changes.

9. In a turbine, the combination of its casing with a vertical shaft, aguide bearing therefor having a spherical seat, a step hearing carriedby the casing and changing its position with casing distortions andcomprising members, one of which is keyed to the shaft and the other isheld against rotation in the housing, the opposed working surfaces ofsaid members being spherical and struck from the same center as saidseat, a housing for supporting the bearings and guiding the verticalmovements of the lower member, and a packing which prevents air and alsolubricant from the bearings from entering the turbine.

10. In a turbine, the combination. of its casing with a vertical shaft,a guide-bearing therefor having a spherical seat formed of twodetachable heads, a step bearing carried by the casing and changing itspos tion with casing distortions and comprising members, the opposedsurfaces of whicn are spherical and struck from the same center as saidseat, a housing for the bearings which is rigid with the casing of theturbine and carries both of said heads, and a packing for preventingleakage between the turbine casing and the bearings which is supportedby one of said heads.

in witness whereof, I have hereunto set my hand this fourth day ofMarch, 1907.

RICHARD ii. men.

Witnesses JOHN A. MOB/limos, J11, PHILIP F. HARRINGTON.

Copies of this patent; may be obtained for five cents each, byaddressing the Commissioner of Patents, Washington, D. C.

